The invention relates to an arrangement for guiding and/or holding electrically conductive sliding contact elements, a contact-making rotary transmission with an arrangement of this type and also a dynamoelectric machine with a contact-making rotary transmission.
With dynamoelectric machines, for instance generators or drive motors, a current can be extracted from or supplied to a rotor of the dynamoelectric machine by way of a sliding ring unit. With larger dynamoelectric machines, such as generators in wind power plants, generators and their components are now designed to be increasingly more compact in order to optimize costs and installation space in these wind power plants. With a constant size, this results in the sliding ring unit, in other words individual components of the sliding ring unit, being loaded with increasingly higher currents. For this reason the temperatures increase significantly there, particularly on the conductive sliding contact elements, in other words the sliding ring brushes and their holders, in other words the brush holders.
Furthermore, for cost reasons the contact path of the sliding ring surface is not increased in size with increasing outputs, which results in an additional heating inter alia of the sliding ring brush. The increasing thermal stress on these components therefore results in the temperatures of the entire sliding ring unit also increasing to a critical temperature value, and therefore damages may arise to the sliding rings, to the sliding ring brushes and finally to the overall plant.
Furthermore, from a certain size and output of dynamoelectric machines, sliding ring elements with a larger external diameter are used. As a result the holding unit of the conductive sliding contact elements used is also correspondingly larger. Therefore, high temperatures are avoided, since, inter alia, the work area of the sliding ring element is significantly increased in size. However, the overall installation volume is as a result likewise increased in size accordingly.
This ultimately results now in a higher material outlay and material costs due to the generous sizing of the individual components, and on the other hand the external dimensions of a generator likewise increase impermissibly.
A known power transmission arrangement via electric machines is known from DE 100 03 900 A1, wherein in order to achieve adequate cooling sliding rings of support rings are assumed, which are arranged axially one behind the other and are electrically insulated from one another and are air-flushed.
Sliding ring arrangements are also known from DE 32 30 298 A1, DE 103 19 248 A1 and U.S. Pat. No. 4,329,611 A.
The disadvantage here is that particular individual components of the known sliding ring arrangements are thermally overloaded comparatively quickly.